This invention relates to apparatus for releasably securing, or chucking a workpiece for rotation, and more particularly, to apparatus for chucking the core of a roll of web material for rotation of the roll with a shaft.
In the past, a variety of devices have been designed for chucking a workpiece, such as a roll of web material, on a shaft or spindle. Among these devices are tapered cones that are wedged into the cores of the rolls; mechanically actuated, internally expanding jaws; and pneumatically inflatable bladders. Another such device is disclosed in U.S. Pat. No. 3,263,938 issued Aug. 2, 1966 to Herbert F. Dalglish and entitled "Core Clutch". The preferred embodiment of that device includes three elongated, cross-sectionally triangular members positioned in axially elongated, cross-sectionally rectangular grooves cut into the outer surface of the spindle on which the roll is to be chucked. The triangular members are retained by a garter spring positioned in a groove cut about the circumference of the spindle, and are free to slide across the grooves and to rock up to chuck the roll, wedging themselves between the shaft and the core of the roll.
A particularly desirable device for chuck a workpiece is disclosed in U.S. Pat. No. 4,143,829 issued Mar. 13, 1979 to the inventor of this invention. The device of U.S. Pat. No. 4,143,829 includes an off-center chuck blade pivotable to wedge against and chuck a workpiece on a spindle. This invention is an improvement to that device.